Multiple pane

ABSTRACT

A multiple pane includes a pair of glass panels spaced by spacers and sealed at peripheries thereof. The multiple pane includes a plurality of spacers interposed between the pair of glass panels, a hermetic bond that hermetically bonds peripheries of the pair of glass panels to each other and a space between the pair of glass panels that is sealed so as to be in a reduced pressure state. Each of the plurality of spacers is a porous member provided on one glass panel of the pair of glass panels.

This application is a divisional application of U.S. patent applicationSer. No. 14/338,753, filed Jul. 23, 2014, which is a U.S. continuationapplication of PCT International Patent Application NumberPCT/JP2013/001468, filed on Mar. 7, 2013, claiming the benefits ofpriority of Japanese Patent Application Number 2012-050052, filed onMar. 7, 2012 and priority of Japanese Patent Application Number2012-116196, filed on May 22, 2012, the entire contents of which arehereby incorporated by reference.

The present disclosure relates to multiple panes each including a pairof glass panels stacked and a low-pressure space between the pair of theglass panels.

There has been commercialized a multiple pane. In the multiple pane, apair of glass panels are arranged facing each other, and a plurality ofspacers are interposed between the pair of glass panels, and the pair ofglass panels are bonded with a hermetic bond at peripheries thereof, andthus an inside space is defined by the pair of glass panels and thehermetic bond. The air in the inside space is exhausted to reduce thepressure of the inside space.

Such a multiple pane in which the pressure of the inside space isreduced has an air layer with a pressure lower than the atmosphericpressure between the pair of glass panels, and thus it is expected toshow a greater heat insulating effect, a greater condensation-preventioneffect, a greater sound-dampening effect that are greater than those ofa multiple pane in which two glass panels are simply stacked. In recentyears, the importance of saving energy has increased, and therefore themultiple pane including the space whose pressure is reduced hasattracted a great attention as one type of eco-glass. The depressurizedmultiple pane is manufactured by: applying a sealant (e.g., low meltingglass frit) onto the peripheries of the pair of glass panels separatedat a predetermined distance by a plurality of spacers such as metal andceramics; heating the sealant to hermetically bond the peripheries andthus form a space; and thereafter exhausting air in the inside space viaan exhaust pipe made of glass or metal.

For example, Patent document 1 (JP 5-501896 A) and Patent document 2 (JP11-324059 A) disclose the above-mentioned background arts.

SUMMARY Technical Problem

The present disclosure is aimed to provide a multiple pane in whichspacers can be formed easily.

Solution to Problem

The multiple pane according to the present disclosure includes a pair ofglass panels, a plurality of spacers interposed between the pair ofglass panels, and a hermetic bond to hermetically bond peripheries ofthe pair of glass panels to each other. The multiple pane contains aspace formed between the pair of glass panels, and the space is to besealed so as to be in a reduced pressure state. Each of the plurality ofspacers is the porous member formed on one glass panel of the pair ofglass panels.

Advantageous Effects of Invention

In the multiple pane according to the present disclosure, each of aplurality of spacers is a porous member, and therefore the plurality ofspacers with desired shapes can be easily formed at desired positionsbetween a pair of glass panels.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A and 1B are a top view and a cross section illustrating aconfiguration of the multiple pane of Embodiment 1, respectively;

FIGS. 2A and 2B are a top view and a cross section illustrating aconfiguration of the multiple pane of Embodiment 2, respectively;

FIGS. 3A and 3B show examples of spectral reflectance characteristics ofindividual infrared reflective films;

FIGS. 4A and 4B are a top view and a cross section illustrating aconfiguration of the multiple pane of Embodiment 3, respectively;

FIG. 5 is an enlarged view illustrating a shape of a spacer of themultiple pane of Embodiment 3;

FIG. 6 is an enlarged view illustrating another shape of a spacer of themultiple pane of Embodiment 3;

FIGS. 7A and 7B are a top view and a cross section illustrating aconfiguration of the multiple pane of Embodiment 4, respectively;

FIG. 8 is an enlarged view illustrating a configuration of a spacer ofthe multiple pane of Embodiment 4;

FIGS. 9A and 9B are a top view and a cross section illustrating aconfiguration of the multiple pane including spacers arranged indifferent patterns, respectively; and

FIGS. 10A and 10B are a top view and a cross section illustrating aconfiguration of a multiple pane including spacers arranged in otherdifferent patterns, respectively.

The figures depict one or more implementations in accordance with thepresent teaching, by way of example only, not by way of limitations.

DESCRIPTION OF EMBODIMENTS

A multiple pane according to the present disclosure includes: a pair ofglass panels; a plurality of spacers interposed between the pair ofglass panels; and a hermetic bond to hermetically bond peripheries ofthe pair of glass panels to each other. The multiple pane contains aspace formed between the pair of glass panels, the space being to besealed so as to be in a reduced pressure state. Each of the plurality ofspacers is a porous member formed on one glass panel of the pair ofglass panels.

Since the multiple pane according to the present disclosure isconfigured as described above, it is possible to easily form theplurality of spacers with desired shapes at desired positions betweenthe pair of glass panels. Therefore, it is possible to provide themultiple pane with heat insulation properties and sound insulationproperties. Besides, since the spacers are the porous members, thespacers can change their shapes to a predetermined extent, even in astate where the spacers are formed on the glass panel. Therefore, evenin a case where there are slight variations between heights of thespacers on the glass panel, the variations are reduced by changes in theshapes of the spacers when the glass panel with the spacers is attachedto the opposite glass panel. Hence, the spacers are in good contact withthe glass panels in entire faces of the pair of glass panels, and themultiple pane with high strength can be obtained.

In the multiple pane, it is preferable that the plurality of spacers aremade from a mixture of a material to compose the plurality of spacersand a binder, and each of the plurality of spacers has pores formed byremoving the binder. The material to compose the plurality of spacers ismixed with the binder, and parts of the resultant mixture are arrangedat predetermined positions. Subsequently, the binder is removed fromeach part of the resultant mixture. Consequently, formed can be theplurality of spacers having strength enough to keep an interval betweenthe pair of glass panels to a predetermined value.

Besides, each of the plurality of spacers is porous glass. Since beingglass member, the plurality of spacers can be a porous member and formedat desired positions with desired shapes.

Besides, in the multiple pane according to the present disclosure, eachof the plurality of spacers is the porous member and may contain hollowsilica. With this configuration, it is possible to effectively suppressheat transfer via the spacers. Hence, the multiple pane with excellentheat-barrier characteristics may be realized.

Besides, each of the plurality of spacers is the porous member and maycontain a filler made of a heat-resistant ceramic. With thisconfiguration, it is possible to suppress contraction in volume of thespacers.

Furthermore, in this case, the porous member preferably includescrystalized glass. With this configuration, coefficients of thermalexpansion of the plurality of spacers can be close to coefficients ofthermal expansion of the glass panels.

Besides, each of the plurality of spacers is the porous member and maycontain a metal oxide material with electrical conductivity. With thisconfiguration, it is possible to impart infrared reflectivecharacteristics to the spacers, and to realize a multiple pane showinghigher heat insulating performance.

Besides, each of the plurality of spacers has porosity ranging from 1%to 20%.

In the multiple pane according to the present disclosure, it ispreferable that each of the plurality of spacers is the porous memberand includes at least two layers, and the at least two layers includes alayer in contact with one of the pair of glass panels on which thespacers are not formed, and the layer is made of a material having thehighest adhesiveness to glass of materials for the at least two layers.With this configuration, the spacers can be in close contact with theglass panel on which the spacers are not formed, and overall strength ofthe multiple pane can be improved.

Otherwise, it is possible that each of the plurality of spacers is theporous member and includes at least two layers, the at least two layersincludes a layer in contact with one of the pair of glass panels onwhich the spacers are not formed, and the layer has the highestheat-barrier properties of the at least two layers. With thisconfiguration, heat-barrier characteristics of the multiple pane can beimproved more efficiently.

In this regard, the plurality of spacers according to the presentdisclosure are used in a multiple pane. The multiple pane includes apair of glass panels, the plurality of spacers interposed between thepair of glass panels, and a hermetic bond to hermetically bondperipheries of the pair of glass panels to each other. The multiple panecontains a space formed between the pair of glass panels, and the spaceis to be sealed so as to be in a reduced pressure state. Each of theplurality of spacers is the porous member formed on one glass panel ofthe pair of glass panels.

Embodiments will be described below in detail with reference to thedrawings appropriately.

Note that the applicants provide the attached drawings and the followingdescription in order to enable any person skilled in the art tosufficiently understand the present disclosure, and do not intend tolimit the subject matters of claims. For convenience of explanation, thedrawings referred below focus on necessary portions of the multiple panefor describing the present disclosure illustrated in a simplifiedmanner. Therefore, the multiple pane described with reference to thedrawings may have any configuration which is not shown in the drawingsreferred. Furthermore, dimensions of components shown in the drawings donot necessarily reflect dimensions and dimensional ratios of componentsin practice, exactly.

Furthermore, in the present specification, reducing a pressure of aspace to be sealed between the pair of glass panels means allowing thespace between the pair of glass panels to be in a state of having asmaller pressure than the atmospheric pressure of the outside.Furthermore, the reduced pressure state in the present specificationmeans a state in which a pressure of the space to be sealed is smallerthan the atmospheric pressure of the outside. The reduced pressure stateincludes a vacuum state in which air inside the space is exhausted toreduce the pressure of the space, and the vacuum state is not limited bydegrees of vacuum. In this regard, the reduced pressure state in thepresent specification includes a state where at least one of variousgases such as an inert gas is supplied to the space after exhausting theair inside the space, so long as the pressure of the space containingsuch a gas is consequently smaller than the atmospheric pressure.

Embodiment 1

A multiple pane of Embodiment 1 disclosed in the present applicationwill be described below using FIGS. 1A and 1B.

FIG. 1A is a top view of the multiple pane of the present embodiment,and FIG. 1B is a cross section of the multiple pane of the presentembodiment. FIG. 1B shows a cross sectional configuration taken alongthe line A-A′ of FIG. 1A.

As shown in FIGS. 1A and 1B, the multiple pane includes a pair of glasspanels 1 and 2 separated at a distance from each other by a plurality ofspacers 3 which are porous members, and a seal 4, which is a hermeticbond, to hermetically bond peripheries of the pair of glass panels 1 and2 to each other. A space enclosed by the pair of glass panels 1 and 2and the seal 4 is to be sealed. The air in the space is exhausted via anoutlet formed in the glass panel 1 in order to reduce the pressure ofthe space to a predetermined pressure, and then the outlet is sealedwith a metal cap 5, for example. Accordingly, the space becomes a sealedspace in the reduced pressure state.

The glass panel 1 and the glass panel 2 are both formed of a sheet offloat glass with a thickness of 3 mm, for example. The glass panel 1 hasa hole for exhausting, which is used as the outlet and not shown in thedrawings.

The spacers 3 are arranged on the glass panel 2 to keep an intervalbetween the glass panel 1 and the glass panel 2 to a predeterminedvalue. The arrangement pitch of the spacers is, 2 cm, for example. Eachof the spacers has a circular prismatic shape with a diameter of 0.2 mmand a height of 0.2 mm, and is porous glass made of a glass material.Each spacer used in the multiple pane of the present embodiment isporous glass and has a density which can be adjusted by adding lowmelting glass microparticles and adding when requested various inorganicmicroparticles. The spacers are formed on the glass panel 2 byphotolithography.

Each of the spacers according to the present disclosure is the porousmember having a plurality of pores. More specifically, the spacers ofthe present disclosure are made from a paste of a glass material appliedon the glass panel by the photolithography as described above. In theformation of the spacers, organic components used as a binder, varioussolvent such as a photosensitizing agent and an ultraviolet absorber,and resin components including other impurities are mostly vaporized insteps of drying and sintering subsequent to applying, and consequentlythe spacer has the pores that are vacancies of vaporized components. Inthis regard, the pores of the spacer, which is the porous memberaccording to the present disclosure, include both of an open pore whichis exposed on a surface of the spacer and a closed pore which is notexposed on the surface.

Besides, the phrase that “the spacer according to the present disclosureis formed on one glass panel of the pair of glass panels” refers to bothof a case where the spacer is formed directly on the glass panel and acase where the spacer is formed on one or two or more thin films on theglass panel, namely, indirectly formed on the glass panel.

When the spacer is made from a photosensitive paste containing a lowmelting glass material, microparticles of an inorganic material, and abinder by photolithography, the porosity of the spacer which is theporous member ranges from about 1% to 20%, for example. The porosityvaries, depending upon components for the spacer, types of resincomponents such as the binder used for forming the spacer, compositionratios of the photosensitive paste, and manufacturing conditions for thespacer, and the like.

Besides, the spacer according to the present disclosure includes notonly the aforementioned spacer having the pores formed by removing thebinder but also a spacer which is a porous member having pores derivedfrom a pore[s] that a component to compose the spacer originally has.Such a component originally having a pore[s] may be, for example, hollowsilica including a hollow inside itself. In any case, the spacer usedfor the multiple pane according to the present disclosure is the porousmember made of the aforementioned material e.g., glass, and do notinclude a core member made of glass, metal, or the like inside itself,differently from the spacer included in the multiple pane described inthe background art.

The seal 4 is composed of low melting glass frit, for example, andformed by applying the low melting glass frit, with a dispenser forexample, onto the periphery of the glass panel 2 on which the spacers 3have been formed, and then drying the low melting glass frit. The lowmelting glass frit may be: a bismuth-based seal containing 70% or moreBi₂O₃, 15% or less B₂O₃, 15% or less ZnO, and 5% or more mixture oforganic substances such as ethyl cellulose and terpineol; or a fritpaste.

Incidentally, a method of preparing the multiple pane of the presentembodiment will be described.

First, the spacers 3 are formed on the glass panel 2 byphotolithography. The detailed method for preparing the spacers 3 willbe described below. Thereafter, the seal 4 is applied onto the peripheryof the glass panel 2 with a dispenser for example, and then is dried.Next, the glass panel 1 and the glass panel 2 are introduced into afurnace with being arranged to face each other, and heated to melt thelow melting glass frit to bond the peripheries of the glass panels 1 and2 with the seal 4. Thereafter, air inside the space in the multiple panein which the glass panel 1 and the glass panel 2 are bonded is exhaustedvia an outlet with a rotary pump, for example, and thereafter the outletis sealed by bonding the metal cap 5 to the outlet.

An example of a formation of the spacers 3 by photolithography will bedescribed below.

First, as a material for forming the spacer 3, a photosensitive paste isprepared. The photosensitive paste is prepared by compounding variouscomponents such as inorganic microparticles (e.g., silicon dioxide), anultraviolet absorber, a photosensitive polymer, a photosensitivemonomer, a photopolymerization initiator, and low melting glassmicroparticles (e.g., bismuth zinc-based particles) so as to have apredetermined composition, and mixing and dispersing them with atriple-roller or a kneading machine.

The photosensitive paste may contain a filler composed of heat resistantceramic particles such as alumina, zirconia, titan oxide, forsterite,mullite, silicon nitride, aluminum nitride, and silica; or high meltingglass particles. Accordingly, it is possible to suppress volumecontraction in forming the spacer. The high melting glass available asthe filler may have a glass-transition temperature ranging from 570° C.to 1200° C. and a softening temperature ranging from 620° C. to 1200°C., and may have a composition of 15 to 50 wt % silicon oxide, 5 to 20wt % boron oxide, 15 to 50 wt % aluminum oxide, and 2 to 10 wt % bariumoxide, for example.

The viscosity of the photosensitive paste is appropriately adjusted byselecting addition ratios of inorganic microparticles, a thickeningagent, an organic solvent, a plasticizer, and or a precipitationinhibitor, and preferably falls within a range of 200 to 200000 cps.

The specific example of the composition of the photosensitive paste maybe 43 wt % low melting glass microparticles, 10 wt % zinc oxide finepowder, 26 wt % resin components containing a photosensitive monomer, aphotosensitive polymer, a photopolymerization initiator, an ultravioletabsorber, a sensitizer, and an auxiliary sensitizer, and 21 wt % organicsolvent serving as the binder.

Thereafter, the photosensitive paste is applied entirely on a surface ofthe glass panel 2 or partially thereon, namely, on parts of the surfaceof the glass panel 2 on which the spacers 3 are to be formed. Theapplication method may be screen printing, bar-coating, a roll-coating,or the like. The application thickness is adjusted by selecting thenumber of times of application, a mesh of the screen, and a viscosity ofthe paste.

Then, mask exposure is performed with a photo mask being over thephotosensitive paste applied onto the glass panel. The shape anddimensions of the spacers in a cross section in a face direction of theglass panel and the positions of the spacers can be appropriatelyadjusted to desired ones by adjusting a pattern of the mask. The maskused is selected from a negative-type mask and a positive-type mask inaccordance with types of the photosensitive organic components. Anactive light source used in the exposure may emit near-ultraviolet rays,ultraviolet rays, electron beam, or X-rays, for example. Among them, theactive light source to emit ultraviolet rays is preferable, and may be alow-pressure mercury lamp, a high-pressure mercury lamp, anultrahigh-pressure mercury lamp, or a halogen lamp. Among them, theultrahigh-pressure mercury lamp is preferable. Although conditions forthe exposure vary depending on a desired application thickness, theexposure may be conducted for a time of 10 to 30 min using anultrahigh-pressure mercury lamp with an output of 5 to 100 mW/cm², forexample. After the exposure, development is conducted with a developerby immersing or spraying. The developer may be a commercially availablealkaline developer.

Subsequently, sintering is performed in a sintering furnace. Thesintering atmosphere and the temperature vary depending on types of thepaste and the panel, but the sintering may be performed under air orunder nitrogen atmosphere. The sintering may be performed at thesintering temperature ranging 520° C. to 610° C., for example, kept fora time ranging from 10 to 60 min.

In the aforementioned manner, for the multiple pane of the presentembodiment, it is possible to form the spacers 3 of the porous glasseach of which has a predetermined shape in cross section, apredetermined size, and a predetermined height, on the glass panel 2 ata predetermined pitch. Besides, these spacers 3 have high adhesion tothe glass substrate 2.

Furthermore, in the multiple pane of the present embodiment, the spacersare made from the photosensitive material, and therefore can be formedin a smaller size than the known spacers having the core members.Accordingly, when the multiple pane of the present embodiment is usedfor a window, for example, the spacers are small in size and thus it isdifficult for human eyes to detect the spacers. Hence, the windowexcellent in visibility can be realized.

Note that, when the spacers 3 which are the glass porous member and usedin the multiple pane of the present embodiment are made from a pastematerial containing 53 wt % inorganic and glass microparticles, 26 wt %resin components containing a photosensitive monomer, a photosensitivepolymer, and the like, and 21 wt % organic solvent serving as binder,the resultant spacers 3 after sintering contains 99 wt % inorganic andglass microparticles and 1 wt % resin components.

Embodiment 2

A multiple pane of the Embodiment 2 according to the present disclosurewill be described below using FIGS. 2A and 2B.

FIG. 2A is a top view of the multiple pane of the present embodiment,and FIG. 2B is a cross section of the multiple pane of the presentembodiment. FIG. 2B shows a cross sectional configuration taken alongthe line B-B′ of FIG. 2A.

As shown in FIGS. 2A and 2B, the multiple pane of the present embodimentincludes a pair of glass panels 11 and 12 separated at a distance fromeach other by a plurality of spacers 13 each of which is a porousmember, and a seal 14, which is a hermetic bond, to hermetically bondperipheries of the pair of glass panels 11 and 12 to each other. Air ina space enclosed by the pair of glass panels 11 and 12 and the seal 14is exhausted via an outlet formed in the glass panel 11 in order toreduce a pressure of the space to a predetermined pressure, and then theoutlet is sealed with a metal cap 15, for example. Accordingly, thespace becomes a sealed space in the reduced pressure state.

The glass panel 11 and the glass panel 12 are both formed of a sheet offloat glass with a thickness of 3 mm, for example. The glass panel 11has a hole for exhausting which is the outlet and not shown in thedrawings. An infrared reflective film 16 is formed on a surface, whichfaces the glass panel 12, of the glass panel 11, that is, an internalsurface of the multiple pane. The infrared reflective film 16 has afunction of transmitting visible radiation but reflecting infraredradiation.

The infrared reflective film 16 is a thin film of tin oxide (SnO₂), forexample. The infrared reflective film 16 has infrared reflectivecharacteristics of reflecting more amounts of infrared radiation in anapproximate wavelength range of 800 nm to 2000 nm and far-infraredradiation than an amount of visible radiation in the wavelength rangebetween about 400 nm to about 800 nm.

The spacers 13 are arranged on the glass panel 12 at a pitch of 2 cm,for example. Each of the spacers 13 has a circular prismatic shape witha diameter of 0.3 mm and a height of 0.2 mm, and is composed of porousglass made of a glass material. Each of the spacers 13 of the multiplepane of the present embodiment is made of glass microparticles includinghollow silica, for example, and formed on the glass panel 12 byphotolithography. In this regard, the hollow silica has a particlediameter of 10 to 300 nm and a shell thickness of about 1 to 15 nm.

The seal 14 is composed of low melting glass frit, for example, andformed by applying the low melting glass frit, with a dispenser forexample, onto the periphery of the glass panel 12 on which the spacershave been formed, and then drying the low melting glass frit. The lowmelting glass frit may be: a bismuth-based seal containing 70% or moreBi₂O₃, 15% or less B₂O₃, 15% or less ZnO, and 5% or more mixture oforganic substances such as ethyl cellulose and terpineol; or a fritpaste.

A method of preparing the multiple pane of the present embodiment willbe described.

First, on the surface of the glass panel 11 to be opposite the glasspanel 12, the infrared reflective film 16 is formed by CVD, for example.In this regard, the glass panel 11 may be low-reflective glass(generally referred to as LowE glass or the like) including the infraredreflective film 16 at its one surface.

Then, the spacers 13 are formed on the glass panel 12 byphotolithography. The method for preparing the spacers 13 may be thesame as the method described above in Embodiment 1. Thereafter, the seal14 is applied onto the periphery of the glass panel 12 with a dispenser,for example, and then is dried. Subsequently, the glass panel 11 and theglass panel 12 are introduced into a furnace with being arranged suchthat the surface of the glass panel 11 on which the infrared reflectivemembrane 16 has been formed is to be inside the multiple pane, namely,the infrared reflective membrane 16 faces the spacers 13 on the glasspanel 12, and heated to melt the low melting glass frit to bond theperipheries of the glass panels 11 and 12 with the seal 14. Thereafter,air in a space inside the multiple pane in which the glass panel 11 andthe glass panel 12 are bonded is exhausted via an outlet with a rotarypump, for example, and thereafter the outlet is sealed by bonding themetal cap 15 thereto.

As described above, the multiple pane of the present embodimentincludes, at the inside thereof, the infrared reflective film 16 on thesurface of the glass panel 11. Therefore, when the multiple pane of thepresent embodiment is used as a window glass, it is possible to shieldheat from sun light with the infrared reflective film 16, and improve aheat insulating effect between an inside and an outside of a room.Besides, in the multiple pane of the present embodiment, the spacers 13which are the porous members contain hollow silica with the particlediameter of 10 to 300 nm and the shell thickness of about 1 to 15 nm,for example, and therefore the spacers 13 have improved heat insulatingproperties. Hence, it is possible to effectively prevent heat fromtransferring between the pair of glass panels 11 and 12 through thespacers 13. Accordingly, it is possible to further improve heatinsulating characteristics of the multiple pane.

Note that, in the present embodiment, the case of the infraredreflective film made of tin oxide (SnO₂) is described. However, theinfrared reflective film may be made of other oxide such as ITO (Indiumtin oxide) and zinc oxide. Besides, the infrared reflective film may bea multilayer film of silver and oxide which are stacked and formed witha sputtering device.

FIGS. 3A and 3B show examples of spectral reflectance characteristics ofindividual infrared reflective films.

FIG. 3A shows spectral reflectance characteristics of the infraredreflective film which is the tin oxide (SnO₂) film taken as an examplein the present embodiment, and FIG. 3B shows spectral reflectancecharacteristics of the infrared reflective film which is a stack ofsilver and oxide.

The tin oxide (SnO₂) film whose spectral reflectance characteristics areshown in FIG. 3A is formed by CVD (chemical vapor deposition) on theglass panel and has a thickness of 100 μm. As shown in FIG. 3A, theinfrared reflective film of the tin oxide (SnO₂) film has excellentcharacteristics of having reflectance of 10% for radiation in thevisible range of 400 to 800 nm, but having high reflectance of radiationin the infrared range, and in particular, having reflectance of 20% ormore for radiation in the far-infrared range in which the wavelength is1600 nm or more.

The infrared reflective film of the tin oxide (SnO₂) film whose spectralreflectance characteristics are shown in FIG. 3A can be formed by CVDwhich is performed in a high temperature step for manufacturing theglass panel. Therefore, using such an infrared reflective film has anadvantage that the glass panel with the infrared reflective film can beformed at a low cost. Moreover, the infrared reflective film of the tinoxide (SnO₂) film formed in the step at a high temperature has anadvantage of being less likely to deteriorate in a subsequent hightemperature step and under the environment. Hence, as described below,it is possible to form the spacers on the infrared reflective film.Alternatively, the infrared reflective film can be formed on an outersurface of the multiple pane in view of the fact that the above infraredreflective film is less likely to deteriorate due to changes in humidityand temperature, and oil from user's fingers.

The film having a stack configuration of silver and oxide film whosespectral reflectance characteristics are shown in FIG. 3B is an infraredreflective film with a thickness of 100 nm formed by stacking on theglass panel a zinc oxide film with a thickness of 30 nm, a silver (Ag)film with a thickness of 10 nm, a zinc oxide film with a thickness of 20nm, a silver (Ag) film with a thickness of 10 nm, and a zinc oxide filmwith a thickness of 30 nm by CVD. As shown in FIG. 3B, the infraredreflective film with the stack configuration of silver and a zinc oxidefilm has excellent characteristics of having low reflectance ranging 5%to 10% for radiation in the visible range of about 400 to 700 nm, buthaving high reflectance of red light radiation and longer wave radiationthan red light having wavelengths of 750 nm or more, and in particular,having reflectance of about 80% or more for infrared radiation of awavelength of about 1000 nm or more.

As shown in FIG. 3B, the infrared reflective film of stacked films ofsilver and an oxide film has high reflective characteristics with regardto infrared radiation. Therefore, it is possible to improve a shieldingeffect of heat from sun light of the multiple pane including theinfrared reflective film, and obtain a multiple pane showing a high heatinsulating effect. In this regard, an infrared reflective film formed bysputtering is prone to be poor in stability to high temperature and theenvironment, compared with the aforementioned infrared reflective filmformed by CVD. Therefore, it is necessary to pay attention on aninfrared reflective film in a case where a spacer is formed on theinfrared reflective film and/or a case where the infrared reflectivefilm is formed on the outer surface of the multiple pane.

Besides, in the multiple pane of the present embodiment, when a materialfor composing the porous glass of the spacer 13 contains glass,crystallized glass, and a filler such as titanium oxide and zirconium,it is possible to improve strengths of the spacer 13 to mechanical andthermal shocks. The crystallized glass refers to a material, which isformed by dispersing crystals having negative thermal expansionproperties into glass to offset thermal expansion of the glass with thenegative thermal expansion of the crystal and consequently has a smallcoefficient of thermal expansion.

Furthermore, in a case of using a material having a coefficient ofthermal expansion equivalent to the coefficient of thermal expansion ofthe glass panel ranging from 8.5*10⁻⁶ to 9.0*10⁻⁶° C. as the materialfor the spacer 13, it is possible to reduce strain due to stress causedby a difference in the coefficient of thermal expansion in a hightemperature process. Therefore, it is possible to improve strength ofthe multiple pane.

Besides, by selecting the composition of the material composing theporous glass of the spacer 13 so that the material contains anelectrical conductive oxide material such as ITO, zinc oxide, titaniumoxide, and tin oxide, it is possible to impart the infrared reflectivecharacteristics to the spacer 13 itself. Then, owing to the spacers madeof the material with the infrared reflective characteristics, it ispossible to further improve infrared reflective performance of theinfrared reflective film on the glass panel, and therefore to providethe multiple pane showing higher heat insulating performance.

Note that, in above-described Embodiment 2, the example is described inwhich the infrared reflective film 16 is formed on the surface, thatserves as the internal surface of the multiple pane, of the glass panel11 on which the spacers are not to be formed, the glass panel 11 beingone of the pair of glass panels constituting the multiple pane. However,the infrared reflective film 16 may be formed on the surface, whichserves as another internal surface of the multiple pane, of the glasspanel 12 on which the spacers are to be formed. Furthermore, theinfrared reflective films may be individually formed on the internalsurfaces defined by the glass panel 11 and the glass panel 12. In a caseof forming the infrared reflective films on both the pair of glasspanels, it is possible to obtain the multiple pane showing higher heatinsulating effect, compared with a case of forming the infraredreflective film on either one of the glass panels.

In this regard, the infrared reflective film may be formed at theoutside on the glass panel, and in this case, heat insulating effectowing to reflection of infrared radiation can be obtained. However, asdescribed above, the infrared reflective film formed by sputtering, forexample, is susceptible to the surrounding, and therefore there is highpossibility of occurring problems such as deterioration of the infraredreflective characteristics and change in color of the infraredreflective film. Therefore, when the infrared reflective film is formedat the outside on the glass panel composing the multiple pane, it iseffective to adopt a configuration for protecting the infraredreflective film. For example, the method of preparing the infraredreflective film may be modified so that the infrared reflective film isless likely to deteriorate, for example, by changing the material orconfiguration of the infrared reflective film. Furthermore, the infraredreflective film may be covered with a further glass panel or a resinpanel.

Besides, when the infrared reflective film is made of an electricalconductive material, there is possibility of an unfavorable effect dueto electromagnetic shielding, for example, occurrence of a problem thatmobile phones in a room cannot communicate. Therefore, in the case offorming the infrared reflective film on the multiple pane, it ispreferable to design the infrared reflective film in view of theelectromagnetic shielding in addition to the intended infraredreflective characteristics of the infrared reflective film. In designingthe infrared reflective film, the material used for the infraredreflective film may be selected, and it may be determined whether theinfrared reflective film is formed on only one glass panel of themultiple pane or on both of the glass panels.

Embodiment 3

A multiple pane of Embodiment 3 according to the present disclosure willbe described below using FIGS. 4A to 6.

FIG. 4A is a top view of the multiple pane of the present embodiment,and FIG. 4B is a cross section of the multiple pane of the presentembodiment. FIG. 4B shows a cross sectional configuration taken alongthe line C-C′ of FIG. 4A. FIG. 5 is an enlarged view illustrating aconfiguration of primary parts where the spacer is provided in FIG. 4B.

As shown in FIGS. 4A and 4B, the multiple pane includes a pair of glasspanels 21 and 22 separated at a distance from each other by a pluralityof spacers 23 which are porous members, and a seal 24, which is ahermetic bond, to hermetically bond peripheries of the pair of glasspanels 21 and 22 to each other. Air in a space enclosed by the pair ofglass panels 21 and 22 and the seal 24 is exhausted via an outlet formedin the glass panel 21 in order to reduce a pressure of the space to apredetermined pressure, and then the outlet is sealed with a metal cap25, for example. Accordingly, the space becomes a sealed space in thereduced pressure state.

The glass panel 21 and the glass panel 22 are both formed of a sheet offloat glass with a thickness of 3 mm, for example. The glass panel 21has a hole for exhausting, which is the outlet and not shown in thedrawings.

The spacers 23 are arranged on the glass panel 22 at a pitch of 2 cm,for example. Each of the spacers 23 has a circular prismatic shape witha diameter of 0.4 mm and a height of 0.1 mm, and is made of porousglass. With regard to each of the spacer 23 of the multiple pane of thepresent embodiment, as shown in FIG. 5, a cross-sectional shape of thespacer 23 is such a U-shape that a center of a surface of the spacer 23in contact with the facing glass panel 21 is set back.

The seal 24 is composed of low melting glass frit, for example, andformed by applying the low melting glass frit, with a dispenser forexample, onto the periphery of the glass panel 22 on which the spacershave been formed, and then drying low melting glass frit. The lowmelting glass frit may be: a bismuth-based seal containing 70% or moreBi₂O₃, 15% or less B₂O₃, 15% or less ZnO, and 5% or more mixture oforganic substances such as ethyl cellulose and terpineol; or a fritpaste.

A method of preparing the multiple pane of the present embodiment willbe described.

First, the spacers 23 are formed on the glass panel 22 byphotolithography. In the method of preparing the multiple pane of thepresent embodiment, the active light source and exposure conditions forforming the spacers 23 are adjusted so that the central region of thetop face of the spacer is recessed and thus the cross-sectional shape ofthe spacer is the U-shape as shown in FIG. 5. Note that the spacer 23whose the cross-sectional shape is the U-shape so that the recess isformed in the top face as shown in FIG. 5 can be formed by adjusting thesintering temperature in forming the spacer 23 to a relatively lowtemperature in a range of 520° C. to 610° C., for example.

Thereafter, the seal 24 is applied onto the periphery of the glass panel23 with a dispenser for example, and then is dried. Next, the glasspanel 21 and the glass panel 22 are introduced into a furnace with beingarranged to face each other, and heated to melt the low melting glassfit to bond the peripheries of the glass panels 21 and 22 with the seal24. Thereafter, air in a space inside the multiple pane in which theglass panel 21 and the glass panel 22 are bonded is exhausted via anoutlet with a rotary pump, for example, and thereafter the outlet issealed by hermetically bonding the metal cap 25 thereto.

As described above, in the multiple pane of the present embodiment, theface of each spacer 23 in contact with the facing glass panel 21 isformed into an U-shape, and therefore in joining the pair of glasspanels 21 and 22 with the seal 24 with the pair being arranged to be incontact with each other, an end of the spacer 23 is changed in shape tobe fitted on the face of the glass panel 21 that defines the internalface of the multiple pane. Hence, the spacers 23 formed on the glasspanel 22 can compensate for slight variations between the heights of thespacers 23 and deformation of the glass panels 21 and 22.

Besides, as shown in FIG. 6, also in a case where the face of eachspacer 23 in contact with the facing glass panel 21, which is the topface of the spacer, is formed into a projecting shape in which thecenter of the top face projects, the spacers 23 can compensate forslight variations between the heights of the spacers 23 and deformationof the glass panels 21 and 22, similarly to the case where the contactface with the glass panel 21 is formed into the recessed shape. Thespacers having the top face with the projecting shape as shown in FIG.6, can be realized by adjusting the active light source and the exposureconditions in forming the spacers as described above. The spacers 23having the cross section in which the top face is formed into theprojecting shape as shown in FIG. 6 may be formed by adjusting thesintering temperature in forming the spacers 23 to a temperaturerelatively as high as 610° C. to 630° C., for example.

Embodiment 4

A multiple pane of the Embodiment 4 according to the present disclosurewill be described below using FIGS. 7A to 8.

FIG. 7A is a top view of the multiple pane of the present embodiment,and FIG. 7B is a cross section of the multiple pane of the presentembodiment. FIG. 7B shows a cross sectional configuration taken alongthe line D-D′ of FIG. 7A. FIG. 8 is an enlarged view illustrating a partwhere the spacer is provided in FIG. 7B.

The multiple pane as shown in FIGS. 7A and 7B includes a pair of glasspanels 31 and 32 separated at a distance from each other by a pluralityof spacers 33, and a seal 34, which is a hermetic bond, to hermeticallybond peripheries of the pair of glass panels 31 and 32 to each other.Each of the plurality of spacers 33 is a porous glass member andincludes two layers which are stacked, and the cross sectionalconfiguration of one of the spacers 33 is shown in FIG. 8. Air inside aspace enclosed by the pair of glass panels 31 and 32 and the seal 34 isexhausted via an outlet formed in the glass panel 31 in order to reducethe pressure of the space to a predetermined pressure, and then theoutlet is sealed with a metal cap 35, for example. Accordingly, thespace is formed into a sealed space in the reduced pressure state.

The glass panel 31 and the glass panel 32 are both formed of a sheet offloat glass with a thickness of 3 mm, for example. The glass panel 31has a hole for exhausting.

The spacers 33 are arranged on the glass panel 32 at a pitch of 2 cm,for example. Each of the spacers 33 has a circular prismatic shape witha diameter of 0.4 mm and a height of 0.2 mm, and is made of porousglass. Each of the spacers 33 has a two layer configuration in which anupper spacer layer 37 and a lower spacer layer 38 are stacked. The lowerspacer layer 38 is composed of inorganic microparticles of silicondioxide or the like and low melting glass microparticles e.g., bismuthzinc-based microparticles, and the upper spacer layer 37 is formed onthe lower spacer layer 38. The upper spacer layer 37 is preferably madeof a material having a softening temperature lower than the softeningtemperature of the low melting glass contained in the material for thelower spacer layer 38. For example, when the softening temperature ofthe low melting glass contained in the material for the lower spacerlayer 38 is 510° C., the softening temperature of the material for theupper spacer layer 37 is 480° C.

The seal 34 is made of low melting glass frit, for example, and the lowmelting glass frit is applied, with a dispenser for example, onto aperiphery of the glass panel 32 on which the spacers 33 have beenformed, and then dried. Thereafter, the glass panel 32 and the glasspanel 31 are introduced into a funeral with being arranged so as to faceeach other, and then heated to melt the low melting glass frit to joinand seal them. At the time, the low melting glass contained in the upperspacer layer 37 is melt and then set. Therefore, close contact is madebetween the glass panel 31 and the spacers 37.

A method of preparing the multiple pane of the present embodiment willbe described below.

First, the lower spacer layers 38 are formed on the glass panel 32 byphotolithography. In this regard, the lower spacer layers 38 aresubjected to the steps of application and drying of the photosensitivepaste and exposure in a manufacturing process using photolithography.Then, a photosensitive paste for the upper spacer layer 37 is appliedonto the photosensitive paste for the lower spacer layer 38 yet to bedeveloped, then dried, and subjected to exposure. After the exposure,the photosensitive pastes for the upper spacer layer 37 and for thelower spacer layer 38 are developed at one time, and then sintered.Consequently, the spacers 33 with the two layer configuration areformed.

Thereafter, the seal 34 is applied onto the periphery of the glass panel32 with a dispenser for example, and then is dried. Next, the glasspanel 31 and the glass panel 32 are introduced into a furnace with beingarranged to face each other, and heated to melt the low melting glassfit to bond the peripheries of the glass panels 1 and 2 with the seal34. Thereafter, air in a space inside the multiple pane in which theglass panel 31 and the glass panel 32 are bonded is exhausted via anoutlet with a rotary pump, for example, and thereafter the outlet issealed by bonding the metal cap 35 thereto to form a sealed space whosepressure is reduced.

As described above, since the multiple pane of the present embodimentincludes the spacers with the two layer configuration, adhesion betweenthe glass panel 31 and the spacers 33 is improved, and consequently,overall strength of the multiple pane is improved.

Besides, in the multiple pane as described in the present embodiment,when the upper spacer layer 37 contains a heat shielding material suchas hollow silica, heat transfer between the pair of glass panels isreduced. Hence, heat insulating properties of the multiple pane can beimproved.

According to the applicant's study, in the case of using the spacershaving the two layer configuration used in the multiple pane of thepresent embodiment, when either one of the upper spacer layer and thelower spacer layer contains a heat shielding material, heat insulatingeffect shown by the multiple pane can be increased. Furthermore, in thecase, when the upper spacer layer is selected to have heat shieldingproperties, the heat shielding effect is more improved, compared withwhen the lower spacer layer is selected to have heat shieldingproperties. Specifically, in an example, an upper spacer layer with heatshielding properties composed of low melting glass containing 10 wt %hollow silica was formed on a lower spacer layer with a thickness of0.07 mm made of low melting glass fine powder and had the thickness of0.05 mm. Furthermore, in another example, an upper spacer layer with nospecial heat shielding properties composed of low melting glass alonewas formed on a lower spacer layers with a thickness of 0.07 mm made ofthe same low melting glass fine powder as the former example, and hadthe thickness of 0.05 mm. Consequently, the spacers of the two exampleshad the two layered configuration and the total thickness of 0.12 mm.The thermal conductivity of the spacer with heat shielding properties ofthe former example was about 97% based on the thermal conductivity ofthe spacer with no special heat shielding properties of the latterexample.

Besides, the spacers necessarily do not have the configuration where twolayers are stacked, and may have a configuration where three or morelayers are stacked. When the spacers have the configuration where threeor more layers are stacked, in order to improve strength of the multiplepane by increasing adhesion of the spacers to the facing glass panel,the uppermost layer spacer is preferably made of a material having a lowsoftening temperature. In addition, also in the case where the spacerscontain the material with high heat shielding properties such as hollowsilica, and have a layered formation, the uppermost layer of the spaceris preferably made of a material with the highest heat shieldingproperties.

Note that, in the case of forming the layers of the spacer having thetwo layer configuration both by photolithography, the spacer isnecessarily not formed in the aforementioned manner. For example, thephotosensitive paste for the upper spacer layer 37 may be applied, afterdevelopment and sintering of the lower spacer layer 38. Otherwise, thelower spacer layer 38 is formed by photolithography, and then the upperspacer layer 37 may be formed by screen printing or other printing.

Other Embodiments

As described above, the multiple panes according to the presentdisclosure are specifically described using Embodiments 1 to 4 asexamples of the multiple pane. However, the multiple panes according tothe present disclosure are not limited to these embodiments, and mayinclude embodiments modified by appropriate changes, substitutions,addition, and omission. Besides, the multiple panes according to thepresent disclosure may include new embodiments obtained by combiningcomponents described in Embodiments 1 to 4.

Incidentally, other embodiments than Embodiments 1 to 4 will bedescribed collectively.

In the aforementioned embodiments, described is the step of forming thesealed space in the reduced pressure state by joining the pair of glasspanels with the seal and subsequently exhausting the air in the spaceinside the multiple pane. However, this step may be substituted by astep of joining the pair of glass panels by melting the seal in parallelwith exhausting the air in the space inside the multiple pane.

In the aforementioned embodiments, the air in the space inside themultiple pane is exhausted and subsequently the outlet is bonded to themetal cap to be sealed, for example. However, an outlet tube which is aglass tube may be attached to the outlet, the air in the space insidethe multiple pane may be exhausted via the outlet tube, and thereafterthe outlet tube may be cut by melting the outlet tube to seal the space.

In the aforementioned embodiments, the glass panel composing themultiple pane is formed of float glass, for example. However, the glasspanel may be not only made of float glass but also be a glass panel madeof soda-lime glass, high-strain glass, chemically toughened glass,physically toughened glass, non-alkali glass, quartz glass, Neoceram,borosilicate glass, or Tempax.

In the aforementioned embodiments, the pair of glass panels have thesame outer shape and the same thickness (3 mm, for example), forexample. However, it is not intended to prevent that dimensions and/orthe thickness of one glass panel are different from those of the otherglass panel. Besides, the dimensions of the glass panel may varydepending on the application, and include a length of one side severalcm, at smallest, or a length of one side about 2 to 3 m, at maximum foruse of a window glass. The thickness of the glass panel may varydepending on the application, and may be about 2 to 3 mm at smallest, ormay be about 20 mm at greatest.

In the aforementioned embodiments, the spacer is described as a spacerwith such an approximately circular prismatic shape that a horizontalsectional shape of the spacer is circular, for example. However, theshape of the spacer is not limited to the circular prismatic shapedescribed above, but may be selected from various shapes such as aprismatic shape having a horizontal sectional shape in the facedirection of the glass panel being rectangular, triangular, orpolygonal.

Besides, the dimensions of the spacer are not limited to those describedabove, and are selected appropriately in accordance with the size andthe thickness of the glass panel used, the interval between the glasspanels, and the like.

An arrangement pattern, an arrangement pitch, a size distribution on theglass panel of the spacers are appropriately selected.

FIGS. 9A and 9B show the first example of the multiple pane havingvariations both in the arrangement pitch of the spacers on the glasspanel and in the size distribution of the spacers, the size referringthe dimensions of the spacer in the face direction of the glass panel.FIG. 9A is a top view of the first example of the multiple pane, andFIG. 9B shows a cross sectional configuration of the first example ofthe multiple pane. FIG. 9B also shows a cross sectional configurationtaken along the line E-E′ of FIG. 9A.

As shown in FIGS. 9A and 9B, in the first example of the multiple panehaving variations in the arrangement pitch and the size distribution ofthe spacers on the glass panel, the spacers between the pair of glasspanels 41 and 42 include spacers 43 at a peripheral region and spacers44 at a central region. The spacers 43 at the peripheral region have asmaller size than that of the spacers 44 at the central region. Besides,the spacers 43 at the peripheral region are arranged at a narrowerarrangement pitch than that for the spacers 44 at the central region.Specifically, the arrangement pitch for the spacers 43 at the peripheralregion is 1.5 cm and the arrangement pitch for the spacers 44 at thecentral region is 2.0 cm, for example. Besides, the diameter of thespacers 43 at the peripheral region is 0.3 mm while the diameter of thespacers 44 at the central region is 0.5 mm. Owing to variations in thearrangement pitch and the size of the spacers formed on the glass panel42 as described above, when an external force is applied on theperiphery of the multiple pane, more spacers can receive the externalforce and distribute it. Hence, it is possible to effectively preventbreakage of the multiple pane and peeling of the seal 45.

FIGS. 10A and 10B show the second example of the multiple pane havingvariations both in the arrangement pitch of the spacers on the glasspanel and in the size distribution of the spacers, the size referringthe dimensions of the spacers in the face direction of the glass panel.FIG. 10A is a top view of the second example of the multiple pane, andFIG. 10B shows a cross sectional configuration of the second example ofthe multiple pane. FIG. 10B also shows a cross sectional configurationtaken along the line F-F′ of FIG. 10A.

As shown in FIGS. 10A and 10B, in the second example of the multiplepane having variations in the arrangement pitch and the sizedistribution of the spacers on the glass panel, the spacers includespacers 53 at a peripheral region and spacers 54 at a central region.The spacers 53 at the peripheral region have a greater size than that ofthe spacers 54 at the central region. Besides, the spacers 53 at theperipheral region are arranged at a wider arrangement pitch than thatfor the spacer 54 at the central region. Specifically, the arrangementpitch for the spacers 53 at the peripheral region is 2.0 cm, and thearrangement pitch for the spacers 54 at the central region is 1.5 cm,for example. Besides, the diameter of the spacers 53 at the peripheralregion is 0.5 mm, and the diameter of the spacers 54 at the centralregion is 0.3 mm. Owing to variations in the arrangement pitch and thesize of the spacers formed on the glass panel 52 as described above,when the multiple pane is used as a window pane, for example, thespacers near the seal are small and therefore are less likely to bevisually perceived. Hence, a multiple pane excellent in appearance canbe obtained. Furthermore, an interval between the spacers 53 which areat the central region and far from the seal is smaller, and the spacers53 have a smaller diameter in a horizontal direction. Therefore, it ispossible to realize the multiple pane which includes the spacers lesslikely to be visually perceived and nevertheless is capable ofsuppressing a change in the shape of the multiple pane caused by flexureof the glass panels.

Note that in the examples of the multiple pane shown in FIGS. 9A and 9Band the multiple pane shown in FIGS. 10A and 10B, the variations in thearrangement pitch and the size of the spacers depend on a position ofthe spacer on the glass panel, and a region on the glass panel isclassified into two regions of the peripheral region and the centralregion, and, in each of the peripheral region and the central region,the size and the arrangement pitch for the spacers are constant.However, the multiple pane according to the present disclosure mayinclude three or more regions of which the arrangement pitches and thesizes of the spacers are different from each other. Furthermore, in eachof the regions, the arrangement pitch and/or the size of the spacers mayvary in a stepwise manner. Besides, instead of dividing the glass panelinto such regions, the pitch and/or the size of the spacers may vary ina stepwise manner from one edge to another edge, for example.

Besides, by making use of the fact that the spacers used in the multiplepane of the present disclosure are formed by the photolithography, byadjusting the pattern of the exposure mask, the spacers can be arrangedon the glass panel of the multiple pane to show a pattern that isperceived by a user as being meaningful.

The pattern that is represented by the arrangement of the spacers and isperceived as being meaningful may include various words such as theproduct name of the multiple pane. Furthermore, the various words mayinclude a name and a telephone number of a shop, when the multiple paneis used for a show window of the shop. Similarly, such a pattern mayinclude logos of the multiple pane per se and/or a manufacturer of themultiple pane. Furthermore, when the multiple pane is used as a windowpane of a shop or a facility or when the multiple pane is used as awindow of an information research system box for a public internetterminal or the like, such a pattern may include figures and/or symbolsrecognized as a meaningful mark providing various meanings e.g., a marksymbolizing services the facility can provide.

Note that a method of preparing the pattern of the spacers recognized asbeing meaningful may be a similar method of arranging dots to formpredetermined words or figure as a whole, or a method of adjusting thepattern of the exposure mask so as to form the spacers having shapes ofdesired words or figures as they are. The method of arranging dots toform words or figure as a whole is conducted by adjusting a degree ofdensity, which is the arrangement pitch, of the spacers and/or adjustinga shape or dimensions of the cross section of the spacers in ahorizontal direction.

Besides, by applying the technique of varying the arrangement pitch andsize of the spacers in an entire region over the glass panelconstituting the multiple pane as described above using FIGS. 9A to 10B,it is possible to form gradation of light and shade on an entire surfaceof the glass panel and/or form a pattern such as a check pattern and azigzag pattern.

Furthermore, by varying color, reflectivity, and luster of a materialfor constituting at least part of the spacer depending on a formationregion, the meaningful pattern defined by the spacers may be formed as acolored pattern. As such a method of varying the color of the spacers, amethod of applying a photosensitive paste with desired colors onindividual parts of the glass panel is effective. Besides, when thespacers with the two layer configuration are used like Embodiment 4described using FIGS. 9A and 9B, the upper spacer layer is formed byprinting, for example, it is remarkably facilitated to form spacers witha desired color in a desired region.

In each of the multiple panes of embodiments according to the presentdisclosure, the glass panel is in a flat plate shape. However, themultiple pane according to the present disclosure includes a multiplepane using curved glass panels having strength which is not less than apredetermined value even in a state where the inside of the multiplepane has a reduced pressure. Examples of the curved glass panel include:a glass panel which is curved in one direction; a glass panel which iscurved in all directions like a shape of parts of a sphere; and a glasspanel with a wave-like shape having some units with asperity. Besides,the pair of glass panels need not have the completely same curvaturedegree. In the multiple pane, a distance between two glass panels mayvary according to positions, within a range in which the spacers with adesired height can be formed.

These multiple panes using the curved glass panels are curved as awhole, and therefore exhibit high designability when used in a windowand has high usefulness because they are available in cases where it isnot possible to use a planar multiple pane in view of constraints onshapes for members to be fitted.

Besides, by forming a predetermined printed pattern on parts whoseappearance is not good such as the seal to seal the multiple pane andthe outlet, the multiple pane may have high designability.

Note that the infrared reflective film as formed in the multiple pane ofEmbodiment 2 described using FIGS. 2A and 2B may be included in theconfigurations of the multiple panes of Embodiment 3, Embodiment 4, andthe other embodiment having various variations. By being configured toinclude the infrared reflective film, the multiple panes can showimproved heat insulating effect in addition to the individual featuresof configurations of the individual embodiment.

Besides, in the multiple pane according to the present disclosure, whenthe seal is made of a sealant which melts at a relatively lowtemperature e.g., 300° C., the material to compose the spacers may be aresin material. For example, the porous material may be formed of byadding an inorganic material such as silicon dioxide, titanium dioxide,crystallized or amorphous glass fine powder, and hollow silica, into theresin material instead of a low melting glass material.

Besides, already established techniques related to the multiple pane maybe appropriately added to and applied in the multiple pane according tothe present disclosure. The already established technique includes aformation of an organic or inorganic film in order to impart, to theglass panel, various optical properties of antireflection and/orabsorbing ultraviolet rays, or functions of heat insulatingcharacteristics and the like.

Furthermore, by using the multiple pane per se as at least one glasspanel of the pair of glass panel, a multiple pane may be composed ofthree or more glass panels in total which are stacked and separated by apredetermined space individually. In this case, the multiple paneaccording to the present disclosure may be contained as a part in athickness direction of a multiple pane. Therefore, the multiple paneaccording to the present disclosure may include various mode such as amode where a multiple pane containing enclosed inert gas between thepair of glass panels is provided on the multiple pane according to thepresent disclosure, a mode where a multiple pane formed by the methodaccording to the present disclosure or another method is furtherprovided on the multiple pane according to the present disclosure, amode where a multiple pane in which glass panels are simply stacked at apredetermined interval and a space therebetween still has theatmospheric pressure is provided on the multiple pane according to thepresent disclosure.

Note that the multiple pane according to the present disclosure issuccessfully used as a window pane serving as eco-glass which shows ahigh heat insulating effect and is easy to be handled. Besides,application for household use or business use is expected because themultiple pane provided in a refrigerator or a freezer does not interferewith functions of the refrigerator or the freezer and allows an innercondition to be confirmed.

As described above, the applicant provides an embodiment that theapplicant considers as the best mode, and other embodiments using theattached drawings and/or the detailed description. These are providedfor the purpose of exemplifying the subject matters of claims forpersons skilled in the art by reference to the particular embodiment.Therefore, the components shown in the drawings and described in thedetailed description includes not only essential components for solvingthe problem but also the other components. Hence, by reason of beingillustrated in the drawings and/or described in the detaileddescription, these non-essential components are not to be recognizedimmediately as being essential. Furthermore, within a range includingclaims and equivalents to the claims, various modification,substitution, addition, and omission may be performed regarding theaforementioned embodiment.

While the foregoing has described what are considered to be the bestmode and/or other examples, it is understood that various modificationsmay be made therein and that the subject matter disclosed herein may beimplemented in various forms and examples, and that they may be appliedin numerous applications, only some of which have been described herein.It is intended by the following claims to claim any and allmodifications and variations that fall within the true scope of thepresent teachings.

A multiple pane according to the first aspect of the present disclosureincludes: a pair of glass panels; and a plurality of spacers interposedbetween the pair of glass panels to keep a distance between the pair ofpanels to be constant. Peripheries of the glass panels are hermeticallybonded. The multiple pane contains a space to be sealed between theglass panels, and the space is in reduced pressure state. Each of thespacers includes at least one layer of a porous member.

In the multiple pane according to the second aspect of the presentdisclosure referring to the first aspect, each of the spacers is porousglass.

In the multiple pane according to the third aspect of the presentdisclosure referring to the first or second aspect, at least one glasspanel of the pair of glass panels has a film which allows visibleradiation to pass therethrough but reflects infrared radiation.

In the multiple pane according to the fourth aspect of the presentdisclosure referring to any one of the first to third aspects, theporous member contains hollow silica.

In the multiple pane according to the fifth aspect of the presentdisclosure referring to any one of the first to third aspects, theporous member contains crystalized glass and filler.

In the multiple pane according to the sixth aspect of the presentdisclosure referring to any one of the first to third aspects, theporous member contains a metal oxide material with electricalconductivity.

In the multiple pane according to the seventh aspect of the presentdisclosure referring to any one of the first to third aspects, theporous member has a face in contact with the glass pane, and the face isin an U-shape or a projecting shape.

In the multiple pane according to the eighth aspect of the presentdisclosure referring to any one of the first to third aspects, each ofthe plurality of spacers is a porous member and contains two layers. Alayer of the two layers is in contact with the glass panel and made of amaterial having adhesion to glass.

In the multiple pane according to the ninth aspect of the presentdisclosure referring to any one of the first to third aspects, each ofthe plurality of spacers is a porous member and contains two layers. Alayer out of the two layers is in contact with the glass panel and madeof a material having heat-barrier properties.

In the multiple pane according to the tenth aspect of the presentdisclosure referring to any one of the first to ninth aspects, aninterval between spacers on a peripheral region of the glass panel isdifferent from an interval between spacers on a central region of theglass panel.

In the multiple pane according to the eleventh aspect of the presentdisclosure referring to any one of the first to ninth aspects, a size ofthe spacers on a peripheral region of the glass panel is different froma size of the spacers on a central region of the glass panel.

A method of preparing a multiple pane according to the twelfth aspect ofthe present disclosure, includes: arranging a pair of glass panels so asto face each other and be separated from each other at a predetermineddistance by a spacer; bonding peripheries of the pair of glass panels toform a space to be sealed between the glass panels; making the space bein a reduced pressure state, in which the spacer is made from aphotosensitive paste and includes one or more layer of porous glass.

INDUSTRIAL APPLICABILITY

As described above, a multiple pane according to the present disclosureis highly useful, and can be used in various applications such as awindow pane, a window member for looking inside a refrigerator, and thelike, as a highly useful multiple pane.

1. A multiple pane comprising: a pair of glass panels; a plurality ofspacers interposed between the pair of glass panels; and a hermetic bondthat hermetically bonds peripheries of the pair of glass panels to eachother, the multiple pane comprising a space provided between the pair ofglass panels, the space configured to be sealed so as to be in a reducedpressure state, each of the plurality of spacers being a porous memberprovided on one glass panel of the pair of glass panels, the porousmember including at least two layers, the at least two layers includinga layer in contact with one of the pair of glass panels on which thespacers are not provided, and the layer having the highest adhesivenessto glass of the at least two layers.
 2. The multiple pane according toclaim 1, wherein the plurality of spacers comprise a mixture of amaterial of the plurality of spacers and a binder, and each of theplurality of spacers has pores formed by removal of the binder.
 3. Themultiple pane according to claim 1, wherein each of the plurality ofspacers is the porous member containing a filler of a heat-resistantceramic.
 4. The multiple pane according to claim 1, wherein each of theplurality of spacers has a porosity ranging from 1% to 20%.